Material Removal from Surfaces

ABSTRACT

Scrapers for removing adhered material from surfaces employ continuous and discontinuous material removal edges to remove different types of material. Continuous and sometimes discontinuous material removal edges are constructed and arranged to conform to the curvature of a surface from which material is to be removed, when a user forces the scraper against the surface. Some scrapers include multiple material removal edges designed to simultaneously contact the surface. The use of multiple points of contact combined with locations of handles provide stable designs that reduce hand and wrist strain.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit from U.S. Provisional Patent ApplicationNo. 62/311,954, filed Mar. 23, 2016, the contents of which areincorporated herein by reference in its entirety.

BACKGROUND

This disclosure relates to removing adhered material from a surface, andin particular to removal of frozen material from environmentally exposedsurfaces such as window and windshield glass of motor vehicles. Priorart devices suffer from a number of problems such as: poor ergonomics,failure to remove material over a wide path causing inefficiency inmaterial removal, and use of material removal surfaces that are easilydamaged. Additionally, prior art devices may be large and bulky and maynot easily fit in available storage spaces.

SUMMARY

Examples of scrapers for removing adhered material from surfaces aredisclosed herein. Examples employ continuous and discontinuous materialremoval edges. The scrapers are constructed such that material removaledges can conform to the curvature of a surface from which material isto be removed, when a user applies a force to push the scraper againstthe surface. Various scrapers include multiple material removal edgesdesigned to simultaneously contact the surface. The use of multiplepoints of contact combined with locations of handles provide stabledesigns that reduce hand and wrist strain. Numerous other improvementsand advantages are described. All examples and features mentioned belowcan be combined in any technically possible way.

In one aspect, a scraper for removing adhered material from a surfacehaving a curved shape comprises a first material removal wall comprisinga first material removal edge which is continuous, where the firstmaterial removal edge is capable of being deformed to conform to theshape of the surface, a second material removal wall comprising a secondmaterial removal edge which is discontinuous, where the first and secondmaterial removal edges are spaced apart from each other, a handle forgripping the scraper, where a projected location of the handle islocated between projected locations of the first and second materialremoval edges, a first structure that is coupled to the first materialremoval wall near the first material removal edge and to one or both ofthe handle and the second material removal wall forming a first truss,where the first truss variably transforms bending loads applied to thefirst material removal edge into tension and compression loads in thefirst truss, wherein the handle is mechanically coupled to top ends ofthe first and second material removal walls opposite the ends of thefirst and second material removal walls incorporating the first andsecond material removal edges, wherein the scraper is constructed andarranged so that the continuous and discontinuous material removal edgescan make simultaneous contact with the surface, and included angles,formed between the first and second material removal walls and thesurface when both the continuous material removal edge and thediscontinuous material removal edge of the scraper are in contact withthe surface are effective for scraping.

Embodiments may include one of the following features, or anycombination thereof. The first material removal edge is pre-biased tohave curved shape in an unloaded condition. The first structure couplesto the midpoint of the first material removal wall and also couples tothe second material removal wall. A second structure coupled to thefirst material removal wall near the first material removal edge, and toone or both of the handle and the second material removal wall forming asecond truss, wherein both the first and second trusses comprise trusspanels, wherein the first and second trusses variably transform bendingloads applied to the first material removal edge into tension andcompression loads in the second truss, wherein the first and secondtrusses form first and second side walls of the scraper. The first andsecond truss panels are open. The openings in the first and second trusspanels are not large enough to allow a user's thumb to fully penetratethrough the opening. The first material removal edge is made of brass.The second material removal edge is made of brass. The scraper isconstructed and arranged such that it can fit into typical sized gloveboxes and storage bins of automotive vehicles. When the scraper ispressed against a surface having a radius of curvature greater than orequal to 1.5 meters with a force applied to the handle of 50N, the forceapplied by the first material removal edge to the surface is at least 10N at every point along the width of the first material removal edge. Thewidth of the first material removal edge is at least 100 mm.

The handle is mechanically coupled to top ends of first and secondmaterial removal walls over the entire widths of top ends of the firstand second material removal walls. The handle is arranged such that thepalm of a user's hand can rest on the handle and the user's fingers canrest on either of the first or second material removal walls, to allowthe user to apply a force to the handle with their palm and to apply aforce to either of the first or second material removal walls with theirfingers. The projected location of the center of mass of the scraper islocated between the projected locations of the first material removaledge and the second material removal edge. When the first and secondmaterial removal edges are in contact with the surface, the handle issufficiently above the surface so that the user's thumb and littlefingers can rest on the side walls of the scraper without interferencefrom the surface. The included angles are between 30 and 60 degrees. Thefirst and second material removal edges are spaced apart a distancegreater than 70 mm. The first truss has a shape that can be triangularor trapezoidal. The width of the second material removal edge isnarrower than the width of the first material removal edge.

In one aspect, a scraper for removing adhered material from a surfacecomprises a first material removal wall comprising a first continuousmaterial removal edge and a second material removal wall comprising asecond continuous material removal edge, wherein the first and secondmaterial removal edges are spaced apart from each other, wherein thefirst and second material removal edges are capable of being deformed toconform to the shape of the surface, a handle for gripping the scraperlocated between projected locations of the first and second materialremoval edges, wherein the handle is mechanically coupled to top ends ofthe first and second material removal walls, opposite ends of the firstand second material removal walls that incorporate the first and secondmaterial removal edges, wherein the scraper further comprises a firststructure coupled to the first material removal wall near the firstmaterial removal edge and coupled to the second material removal wallnear the second material removal edge forming a first truss, to variablytransform bending loads applied to the first material removal edge andthe second material removal edge into tension and compression loads inthe first truss, wherein the scraper is constructed and arranged suchthat the first and second material removal edges can make simultaneouscontact with the surface, and wherein included angles, formed betweenthe first and second material removal walls and the surface when boththe first material removal edge and the second material removal edge ofthe scraper are in contact with the surface, are effective for scraping.

Embodiments may include one of the following features, or anycombination thereof. The first material removal edge is pre-biased tohave curved shape in an unloaded condition. The second material removaledge is pre-biased to have curved shape in an unloaded condition. Thepre-biased curvature of the first material removal edge is differentfrom the pre-biased curvature of the second material removal edge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art scraper

FIG. 2A is a perspective view on one example scraper.

FIG. 2B is a top view of the example scraper depicted in FIG. 2A.

FIG. 2C is a side view of the example scraper depicted in FIG. 2A.

FIG. 2D is a view of the underside of an example scraper using a singletruss structure.

FIG. 2E is a view of the underside of an example scraper using analternative truss structure.

FIG. 2F is a perspective view of another example scraper including acontinuous material removal edge pre-biased into a concave curved shape.

FIG. 3A is a side view of the example scraper depicted in FIG. 2Aincluding an open truss panel.

FIG. 3B is a side view of the example scraper depicted in FIG. 2Aincluding an open truss panel and additional internal truss members.

FIG. 3C is a side view of the example scraper depicted in FIG. 2Aincluding a truss panel with a hole.

FIG. 4A is a side view of an example scraper with an alternative trussstructure which also incorporates an open truss panel.

FIG. 4B is a side view an example scraper with an alternative trussstructure which incorporates a solid triangular truss panel.

FIG. 5A is a perspective top view of a removable scraper blade assembly.

FIG. 5B is a perspective bottom view of a removable scraper bladeassembly.

FIG. 5C is a perspective top view of a removable scraper blade assembly.

FIG. 5D is a perspective bottom view removable scraper blade assembly.

FIG. 5E is a perspective bottom view removable scraper blade assembly

FIG. 6 is a perspective top view of an example scraper incorporating aremovable scraper blade.

FIG. 7 is a perspective view of a discontinuous material removalstructure.

FIG. 8 is an exploded view of a long handle scraper incorporating apivoting blade assembly.

FIG. 9A is a perspective view of an alternative long handle scraperincorporating a pivoting blade assembly.

FIG. 9B is an exploded bottom view of the long handle scraper of FIG.9A.

DETAILED DESCRIPTION

The examples described herein are shown in the context of removingfrozen material such as frost and ice from environmentally exposedsurfaces such as the windows and windshields of a motorized vehicle.However, the principles, features structures and methods depicted in theexamples disclosed herein are applicable in general to the removal ofadhered material (such as paint, stains, surface coatings, frost, ice,etc.) from a wide range of surfaces (wood, plastic, metal, glass, etc.),and are not limited to the removal of frozen material. Example deviceswill be generally referred to as scrapers for ease of description, butuse of the term scraper is not meant to be limiting in any manner.

FIG. 1 shows a typical prior art ice scraper 10 used for removal offrozen material such as frost or ice from an environmentally exposedsurface 5, such as automotive window glass. Frost removal edge 1 is alinear, continuous edge that is placed against the surface 5 (depictedin FIG. 1 as a series of curved lines representing a curved windshieldsurface) for frost removal. Handle 2 is held by a user such that scraper10 is held at an angle with respect to the surface 5, and scraper 10 ismoved forward along surface 5 to remove frost. Ice chipping features 3form a discontinuous material removal edge and are configured to scorechannels into or chip ice that may be frozen on the window glass.Discontinuous material removal edges are ones that make intermittentcontact over their span (the width extent) with a surface from whichmaterial is to be removed. Discontinuous edges such as toothedstructures are useful for chipping, cracking and/or fracturing adheredmaterials such as ice. Scraper 10 must be flipped over from theorientation shown in FIG. 1 to chip or fracture ice using ice chippingfeatures 3. Scraper 10 must be flipped back over to remove chipped icefrom the surface with edge 1.

One drawback to prior art scrapers such as scraper 10 is that the anglewith which scraper 10 is held with respect to surface 5 may vary. Thereis no mechanism to allow the user to stabilize the position in space ofscraper 10 with respect to surface 5. As a result, scraper 10 may not beat an optimal angle for scraping and it can easily slip during use,resulting in an unexpected jerk movement or a user's hand hitting thesurface.

Another drawback to the design of scraper 10 is that the frost removaledge 1 is straight (linear) while automotive vehicle glass is typicallycurved (and often curved in two dimensions) with a radius of curvaturethat typically varies over the glass surface, and that also varies withvehicle design. The contact line between the straight frost removal edge1 and the curved glass surface 5 is necessarily narrower than the actualwidth 6 of the straight frost removal edge 1, thus necessitating moreback and forth scraping action from the user to clear the window offrost, thus reducing efficiency of material removal.

Yet another drawback of prior art scraper 10 is that the user must applya force “couple” in order to hold scraper 10 at an angle relative to thesurface 5. That is, the user's hand must push down on a first portionwhile simultaneously pulling up on a second portion of scraper handle 2,in order to apply a force to surface 5 along the contact line of scraper10 with surface 5. Requiring the user to apply a force couple (ratherthan a simple force) can cause excessive strain of the user's hand andwrist which is undesirable. Application of a force couple requires auser to use the small muscles of the hand and wrist to generate force topush scraper 10 against surface 5. Some users such as the elderly orthose with a degree of arthritis may have difficulty applying sufficientforce with their hands and wrists.

In order for a continuous material removal edge of a scraper toefficiently remove adhered material (such as frost, ice, coatings, paintor other adhered materials) from a curved surface such as vehicle windowand windshield glass, the continuous material removal edge should beable to conform to the shape of the curved surface so that a widersection and ideally the entire width of the continuous material removaledge is in contact with the curved surface. In one non-limiting example,a scraper is constructed and arranged such that a continuous materialremoval edge incorporated therein can conform to the shape a surfacefrom which material is to be removed, to efficiently remove materialfrom the surface. It should be noted that it is not required though itmay be beneficial for a discontinuous edge (typically in the form ofteeth or a linear arrangement of protrusions) to closely conform to theunderlying surface shape in order to fracture ice sufficiently to allowits removal from the surface.

In one non-limiting example, a scraper incorporates both a continuousmaterial removal edge and a discontinuous material removal edge, thescraper constructed and arranged so that both edges simultaneouslycontact an underlying surface, where at least the continuous materialremoval edge is constructed and arranged to conform to the curvature ofthe surface from which material is to be removed. The continuousmaterial removal edge in an unloaded state may be linear or may bepre-biased to have a curvature (either concave or convex). Pre-biasingcontinuous material removal edges is discussed in more detail insubsequent sections of this disclosure. The discontinuous materialremoval edge may also be constructed and arranged to conform to thecurvature of the surface from which material is to be removed. Thediscontinuous edge may be in the form of teeth or an arrangement ofprotrusions from a surface.

In one non-limiting example, a scraper incorporates a pair of continuousmaterial removal edges, where at least one continuous material removaledge is constructed and arranged to conform to the curvature of asurface from which material is to be removed. The second continuousmaterial removal edge may also be constructed and arranged to conform tothe curvature of the surface. Either one of, or both of the continuousmaterial removal edges may be pre-biased into curved shapes in theirunloaded condition.

In general, example scrapers disclosed herein are concerned withremoving material from convex curved surfaces. However, the principlesdisclosed herein can also be applied to scrapers constructed andarranged to conform to curved concave surfaces. Examples constructed andarranged to conform to surfaces with concave curvature are discussed inmore detail below in conjunction with an example scraper depicted inFIG. 2D.

In general, the example scrapers disclosed herein, except those scrapersdisclosed as having elongated handles, are designed to be sufficientlycompact such that they can easily fit in glove boxes and storage bins ofautomotive vehicles.

The input force supplied by a user to example scrapers disclosed hereinis applied to a scraper handle and is transferred through the scraperstructure to a continuous material removal edge. In one non-limitingexample, the pressure applied between the continuous material removaledge and the curved surface at each point along the contact line of thecontinuous material removal edge with the surface exceeds a thresholdpressure needed to remove the adhered material from the curved surface.The associated threshold pressure is a function of the materialcharacteristics, the adhesion characteristics and the surfacecharacteristics, and will vary with the details of the application. Thepressure applied along the continuous material removal edge can behigher than the required threshold pressure. In general, it should notbe lower than the threshold pressure or the material removal edge maynot remove the adhered material at the point where the thresholdpressure is not exceeded.

It has been found empirically that for typical scraping edges used toremove frozen material such as frost from vehicle window glass, a forcegreater than or equal to F_(min) of approximately 10 N should be appliedby the edge to the surface, so that threshold pressure for frost isexceeded. It has also been found empirically that a typical user iscapable of generating a force F_(max) of approximately 50 N to a scraperhandle, when pressing the scraper against a surface with their armextended. The minimum radius of curvature of typical automotive windowsis 1.5 meters. For an automotive application, scrapers disclosed hereinare constructed and arranged such that a continuous material removaledge is capable of conforming to a surface with a radius of curvaturegreater than or equal to 1.5 m, where a force greater than F_(min)between the continuous material removal edge and the surface is obtainedalong the entire width of the continuous material removal edge, when theuser applies a force to the handle less than or equal to F_(max). Theforce F_(min) should be exceeded everywhere along the continuousmaterial removal edge, regardless of the curvature of the surface (thatis, F_(min) should be exceeded when the scraper is used on both curvedand flat surfaces).

The differential deflection needed (maximum deflection anywhere alongthe edge minus minimum deflection anywhere along the edge) by thecontinuous material removal edge is a function of the edge width and theradius of curvature of the surface. As edge width increases, requireddifferential deflection increases. As radius of curvature decreases,required differential deflection increases. In one non-limiting example,a scraper has a continuous material removal edge width greater than 100mm, where the edge is constructed and arranged to conform to surfaceswith radii of curvature greater than 1.5 m with less than 50 N of forceapplied by the user to the handle, while obtaining a force between theedge and the surface of at least 10 N over the entire width of the edge.

For efficient scraping, it is desirable for the entire length of acontinuous material removal edge of a scraper to be in contact with asurface from which material is to be removed. In order for an initiallylinear continuous material removal edge to contact a curved surface overthe entire length of the edge, the initially linear material removaledge must deform to conform to the shape of the curved surface, and mustdeform in a manner that obtains sufficient pressure along the entireportion of the continuous material removal edge in contact with thesurface. For an automotive application, the continuous material removaledge of an ice scraper must be able to conform to the widely varyingcurvatures found in windows and windshields of a typical vehicle andbetween vehicle types.

Example scrapers disclosed herein distribute input force from a user'shand applied when grasping a scraper at a grip location to the materialremoval edge(s), and variably constrain displacement of one or morematerial removal edges along their widths in order to obtain materialremoval edges that conform to a wide range of surface curvatures(including flat). Example scrapers disclosed herein variably transformbending loads applied to a material removal edge into tension andcompression loads in members affixed to material removal walls thatincorporate the material removal edges, where the transformation frombending load to tension and compression load varies across the width ofthe material removal edge(s), to facilitate conforming the materialremoval edge(s) to the shape of the surface from which material is to beremoved. The material removal edge(s) are deformed when a force pressingthe scraper against the surface is applied by a user, so that thematerial removal edge(s) are placed into contact with the surface overtheir entire widths, while achieving a contact pressure that exceeds arequired threshold contact pressure over the contact line of thematerial removal edge(s) with the surface.

It is desirable for the hardness of the material chosen to form thematerial removal edge(s) to be greater than the hardness of the materialto be removed, but less than the hardness of the surface from whichmaterial is to be removed. By choosing a material for the materialremoval edges with a hardness within this range, the scraper will notscratch the surface from which material is to be removed, and thematerial to be removed will not scratch the scraper material removaledges. For the application of removing frozen material (frost, ice,etc.) from a vehicle windshield (where hardness of frozen materialranges around 1.5 Mohs, and hardness of vehicle glass is approx. 4.65Mohs), non-limiting examples of polymer materials with a hardness thatfalls between the hardness of ice and the hardness of vehicle glass areABS, polycarbonate, acrylic, and nylon. It should be noted that thelisted materials are examples only and are not an exhaustive list ofpossible polymer materials. Numerous other polymer materials withsimilar hardness can be used.

In addition to polymer materials, many brasses also have a hardness thatfits within the desired range for the application of removing frozenmaterial from vehicle glass. For example, Cartridge Brass, UNS C26000(260 Brass), H08 Temper flat brass has a Rockwell B hardness of 91 (seematWeb.com), which is approx. equivalent to a Mohs hardness of 3. Brassalso has a higher Young's modulus than most polymer materials whichallows thinner wall sections to be used without exceeding the yieldlimit of the material. When brass is used to form a continuous materialremoval edge, the continuous material removal edge demonstrates animproved ability to hold its edge over time compared to material removaledges formed from polymer materials.

In one non-limiting example depicted in FIGS. 2A-2B, scraper 60 has twospaced apart material removal edges 61 and 62 (edge 62 is more clearlyvisible in the top view of FIG. 2B). Material removal edge 61 spansbetween ends 69 and 70 of material removal wall 63, and is linear andcontinuous in its un-deformed state (i.e. with no force applied by theuser). Material removal edge 62 is a discontinuous toothed structurespanning between ends 79 and 80 of material removal wall 73, and isuseful for chipping, fracturing and/or scoring channels in materialssuch as ice. Material removal edge 61 is located at one end of materialremoval wall 63. Side wall 67 couples between end 69 of material removalwall 63 and end 79 of material removal wall 73. Side wall 68 couplesbetween end 70 of material removal wall 63 and end 80 of materialremoval wall 73. Side walls 67 and 68 also couple to side ends of handle64. Side walls 67 and 68 are depicted as coupling to ends 69, 70, 79 and80 of walls 63 and 73 over their entire lengths, though this is notrequired. Side walls 67 and 68 need only couple to portions of ends 69,70, 79 and 80, and also need not couple to handle 64 at all. In order tocontrol deformation of a material removal edge, it is sufficient for theside walls (or a single load transforming structure as depicted in FIG.2D) to couple to the material removal wall near the location of thematerial removal edge. Side walls need not couple to the materialremoval wall over its entire height. In general, side walls shouldcouple to material removal walls as close to material removal edges asis practical, to control deformation of the edges incorporated in thematerial removal walls, without interfering with the surface. Additionalexamples of side walls 67 and 68 are discussed in more detail below.

The side walls, truss structures, etc. disclosed herein couple tomaterial removal walls to increase the bending stiffness of the materialremoval edge in the proximate region where the coupling occurs. Thecloser these structures couple to the edges, the greater their abilityto alter the local bending stiffness of the edge. When coupling of suchstructures is described as “near” the material removal edge, it is meantthat the coupling is sufficiently close to the edge such that theresulting variation in bending stiffness along the edge is sufficient toallow the edge to conform to a surface of interest with a force input tothe scraper less than or equal to the maximum available force that canbe applied by a typical user (maximum force is described elsewhere inthis disclosure). In general, by nearer, it is meant that a side wall ortruss structure should connect within a distance equal to at least ½ theheight extent of material removal wall, and preferably within ¼ theheight extent of material removal wall.

Bending loads are applied to continuous linear material removal edge 61when scraper 60 is pressed against surface 5 by a user. The bendingloads are transformed into tension and compression loads in side walls67 and 68. The degree to which bending loads are transformed intotension and compression loads varies along the width of edge 61. It canbe seen that the midpoint of the material removal edge 61 (midwaybetween side walls 67 and 68) deforms in bending substantially more thanthe ends of the material removal edge 61 near where the loadtransforming structures 67 and 68 couple to the ends 69 and 70 ofmaterial removal wall 63. This behavior allows material removal edge 61to conform to the curvature of a surface from which material is to beremoved when the material removal edge 61 is pressed against thesurface. In this example, the material removal edge 61 is constructedand arranged to deform to conform to convex surfaces.

It can be seen that handle 64 couples to walls 63 and 73 over the entirewidth of the tops of walls 63 and 73. Handle 64 spans the distancebetween side walls 67 and 68 and allows a user's hand to directly inputforce across the entire span (as opposed to the construction of someprior art devices that couple a handle to a material removal edge viaspaced apart beams that connect the handle directly to ends of thematerial removal edge). The coupling of handle 64 to walls 63 and 73over the entire span allows the user to control the force input to walls63 and 73 across the width of the tops of walls 63 and 73. Thisconstruction allows a user's hand to rest on handle 64 while the user'sfingers can rest on walls 63 or 73 (depending on the orientation inwhich scraper 60 is held). The user can distribute force applied to thehandle 64 anywhere along the tops of walls 63 and 73, which aids inachieving sufficient pressure along the entire lengths of the materialremoval edges. In the non-limiting example scraper 60 depicted in FIGS.2A and 2B, when scraper 60 sits with both material removal edges restingagainst the surface, handle 64 sits above the surface a distancesufficient to ensure the user's hand does not interfere with thesurface, which in this example is approximately 50 mm.

It can be seen in the various figures (FIGS. 2A-C, F among others) thatthe shape of material removal wall 63 of scraper 60 (and scrapers 30 and35 among others) has a slight concave curvature. This is beneficial as auser's hand can fit into this cupped shape. When scraper 60 is used toclear ice where edge 62 faces away from the user, the base of the user'shand rests on wall 63, the middle of the palm rests on handle 64, andthe fingers rest on wall 37. When chipping ice, the scraper may need tobe rammed into ice to crack it, and the cup shape of wall 63 helps holdthe user's hand in place. In general, for example scrapers incorporatinga pair of angled material removal walls incorporating material removaledges arranged so that both edges can contact a surface, where one ofthe material removal edges is discontinuous, the material removal wallopposite the discontinuous edge should have a concave curvature tobetter accommodate the base of a user's hand when chipping ice with thediscontinuous edge.

The user can additionally input force to walls 63 or 73 directly byselectively using his or her fingers to press on walls 63 and 73,further contributing to the ability of the material removal edges toconform to the underlying surface curvature while providing sufficientpressure along the edges. By both coupling handle 64 to material removalwalls 63 and 73 across the entire top span of walls 63 and 73, andallowing the user to use their fingers to input additional force towalls 63 or 73, it is possible to control the variation of force inputby the user to the scraper over the width of scraper 60, and thereforecontrol the variation of the distribution of the input force across thematerial removal edges. Variation of applied force across the width ofmaterial removal edges is controllable by the user by selectively usingtheir fingers/hand to alter input forces across the width of thescraper. The variation of input force across the width is not solelypredetermined by the construction of the scraper as in prior artdevices. Example scrapers as disclosed herein provide for variablytransforming bending loads input to a material removal edge (whethercontinuous or discontinuous) into tension and compression loads intransforming structures described in more detail in subsequent sections,as a function of location across the width of the material removal edge,while also providing the user the ability to selectively andcontrollably vary the input force applied to the scraper across of thewidth of the scraper.

Material removal wall 63 extends from continuous material removal edge61 to the front edge 65 of handle 64, and between side ends 69 and 70.Material removal wall 73 extends from discontinuous material removaledge 62 to the rear end 66 of handle 64, between side ends 79 and 80. Inone non-limiting example, material removal walls 63 and 73 are solid andcontinuous so that a user's fingers can rest on or push against walls 63(or 73) when the palm of the user's hand rests on top of handle 64. Inone non-limiting example, one of wall 63 and 73 incorporates one or moreholes distributed in a manner such that a user's fingers can still exerta force against the wall. It should be noted that the terms “front” and“rear” used above to describe portions of handle 64 are relative termsonly. Scraper 60 can be held and used such that either of materialremoval edges 61 and 62 is oriented towards the “front” and the other isoriented towards the “rear”.

Continuous material removal edge 61 shown (in FIGS. 2A-2C) formed as anintegral part of scraper 60, as may be done if scraper 60 ismanufactured using an injection molding process. In one non-limitingexample edge 75 (shown in FIG. 2F) is formed from a strip of brass (inone example stamped from sheet brass, in another example formed byskiving a roll of brass sheet material and cutting to length, and inanother example formed as an extrusion) in inserted (either using aninsert molding operation or inserting into a slot in a plastic part as asecondary operation) into wall 63 such that the brass strip extends oversubstantially all of the width of wall 63 and extends outward from theend of wall 63 a sufficient distance to allow an edge of the brass stripmaterial to contact surfaces from which material is to be removed to actas the continuous material removal edge. Forming a continuous materialremoval edge from brass can provide substantial improvement over use ofpolymer materials. Brass strip material holds its edge better thantypical polymer materials used for prior art scrapers, and providesimproved scraping performance.

Discontinuous material removal edge 62 is shown as being formed as anintegral part of scraper 60, as may be done if scraper 60 ismanufactured using an injection molding process. Forming a discontinuousmaterial removal edge from brass can provide substantial improvementover use of traditional polymer materials used in prior art scrapers.Discontinuous material removal edges formed of brass are discussed inmore detail in a subsequent section with reference to FIG. 7.

Turning again to FIG. 2B top view of example scraper 60 shows handle 64located between material removal edges 61 and 62 (projected locations ofends 65 and 66 of handle 64 sit inside projected locations of materialremoval edges 61 and 62). Projected locations are locations of anelement projected onto a flat surface on which the scraper rests, withthe scraper placed in its intended orientation for removing materialfrom the flat surface where both material removal edges contact thesurface. Handle 64 provides a surface on which a user's palm can restwhile scraping, where handle 64 is arranged to be generally parallel tothe surface from which material is to be removed when scraper 60 is inplace against the surface with both material removal edges in contactwith the surface. It should be noted that while handle 64 is describedas being generally parallel to the surface, this should not be viewed aslimiting as handle 64 may be arranged with a wide range of angles withrespect to surface 5 when in place against surface 5, so long as a userapplying a force directed towards surface 5 to handle 64 can effectivelyload both material removal edges when both material removal edges are incontact with surface 5.

When a user's hand rests on handle 64, the user's thumb may wrap aroundeither side wall 67 or side wall 68 (depending on whether the user isright or left handed, and what orientation the scraper is being usedin). A user's little finger may rest on the opposite side. Handle 64should extend sufficiently above the surface when both material removaledges are in contact with the surface so that the user's thumb andlittle fingers can rest on the side walls without interfering with thesurface. Side walls 67 and 68 may be solid which reduces the need for aside action in an injection molding tool used to manufacture scraper 60,or may be provided with an indentation or hole or ridge or otherfeatures to accommodate the user's thumb/finger for improved gripping(but may require a side action in tooling). The handle 64 and a portionof walls 63 and 73 form a gripping area, identified by outline 120, andmay have a grip surface applied, such as by overmolding a soft touchelastomer material or affixing with adhesive a die cut piece ofelastomer material to the grip area 120. If desired, soft touch materialcan also be extended around onto a portion of side walls 67 and 68.

It can be seen in FIG. 2A that the bottoms of side wall 67 (and thebottom of side wall 68 which is not visible in FIG. 2A) have a slightcurvature. The bottoms of side walls 67 and 68 are curved sufficientlysuch that no part of the bottom of side walls 67 and 68 will contactsurfaces of interest when scraper 60 sits against the surface with bothmaterial removal edges in contact with the surface. In an automotiveapplication, scraper 60 is designed to accommodate surfaces with aminimum radius of curvature of 1.5 meters. However, this is a designchoice that is primarily centered around a vehicle glass scrapingapplication. The bottom of side walls 67 and 68 could be curved morethan shown if it is required to remove material from surfaces with asmaller radius of curvature. Curving the bottom of side walls 67 and 68does not appreciably affect their structural function for transformingbending loads applied to material removal edges and walls into tensionand compression loads in the side walls (unless the curving isexcessive, for example when the radii of curvature of the bottoms of theside walls is less than 4 times the distance between edges 61 and 62).In one non-limiting example (not shown) the side wall bottoms arestraight, not curved as shown in FIG. 2A. A straight bottom wall ispossible if the attachment point of the side walls to material removalwalls 63 and 73 is displaced a sufficient distance away from materialremoval edges 61 and 62 to ensure the side wall bottom will not contactthe surface when the scraper is pressed against the surface.

Scraper 60 (and other similar scrapers disclosed herein) is constructedsuch that in normal use, the pair of spaced apart material removal edges61 and 62 simultaneously contact surface 5. By incorporating a pair ofspaced apart material removal edges arranged for simultaneous contactwith the surface, and providing a place between the pair of contactpoints with the surface (when viewed in a top view) for a user to applya simple force, it is possible for scraper 60 to remain in a stableposition on the surface while simultaneously orienting material removaledges at angles to the surface sufficient for effectively removingmaterial. That is, the user is not required to apply a force couple(simultaneously pushing down on one part and pulling up on another partof the scraper) to hold scraper 60 against the surface with edgesoriented at a proper angle for material removal, only a simple force isrequired. For example, if light snow were present on a window, a usercould hold the scraper 60 against a window and move it back and forth toremove the snow using a single finger to keep scraper 60 in placeagainst the window.

In some examples, such as the example scraper 60 of FIG. 2A-2B, theprojected location of the center of mass of the scraper 60 (in top view)is located between the projected locations of the pair of materialremoval edges. Scrapers with elongated handles that may have a projectedlocation of a center of mass sitting outside the projected locations ofthe material removal edges are described in subsequent sections.

FIG. 2C depicts a side view of scraper 60. Scraper 60 is constructed andarranged such that material removal walls 63 and 73 which incorporatematerial removal edges 61 and 62 are held at fixed angles 71 and 72relative to the surface 5, when both material removal edges are incontact with surface 5. Angle 71 is the included angle between the planeof the material removal wall 63 (or a tangent plane through dotted axis11 and the material removal edge 61 if wall 63 is curved in the sideview of FIG. 2C) and a plane tangent to the surface 5 at the contactpoint of the material removal edge 61 with the surface (a plane throughdotted axis 12 and material removal edge 61). Angle 72 is calculated ina similar fashion for material removal edge 62, and is the angle betweena plane through dotted axis 13 and edge 62, and a plane through dottedaxis 14 and edge 62. The fixed angles 71 and 72 are chosen to facilitatematerial removal from the surface. In one non-limiting example, angle 71ranges between 10 and 80 degrees. In one non-limiting example, angle 71ranges between 30 and 60 degrees. In one non-limiting example, angle 71ranges between 40 and 50 degrees.

The angle 71 determines how the normal reaction force at the contactpoint of the material removal edge 61 with the surface 5 divides betweenin-plane and an out of plane (bending) components. As the angle 71 getslarger, the in-plane component increases and the out of plane bendingcomponent decreases. The in-plane component is related to how well theedge “digs in” to adhered material on the surface, and the out of planebending component is related to how much the material removal walldeforms to conform to the shape of the surface. Having too much or notenough of either component results in an ineffective scraper (either onethat doesn't conform to the shape of the surface or one that does butslides over adhered material instead of biting into it to dislodge itfrom the surface). The example scrapers disclosed herein maintainmaterial removal walls at desired angles without requiring the user todo anything in particular to achieve it, as long as the two materialremoval edges are placed in contact with the surface.

Referring to FIG. 2C when a downward directed force F₁ is applied by auser to handle 64, normal reaction forces F_(N1) and F_(N2) appear atthe contact point of material removal edges 61 and 62 with surface 5.These normal reaction forces can be decomposed into a pair of orthogonalforce components, where F_(C1) and F_(C2) are components directed in theplanes of walls 63 and 73, and F_(B1) and F_(B2) are components directednormal to the planes of walls 63 and 73. The in-plane force componentsF_(C1) and F_(C2) place walls 63 and 73 in compression. Since the wallsare typically quite stiff in this direction, the in-plane forcecomponents cause little displacement of scraper walls 63 and 73. Thein-plane force components are responsible for the scraper “digging in”to adhered material to remove it from a surface. The orthogonal, out ofplane components F_(B1) and F_(B2) apply bending loads to walls 63 and73 which are the loads of primary interest when trying to construct ascraper with a material removal edge that conforms to the curvature ofan underlying surface from which material is to be removed.

The range of angle for a material removal wall incorporating adiscontinuous material removal edge is not particularly limited, in partbecause conforming to the underlying surface curvature is less importantfor a discontinuous edge. As long as the discontinuous material removaledge is sufficiently stiff to resist damage when impacted with hardmaterials such as ice, it can work effectively to remove material.

Side walls 67 and 68 (discussed in more detail below) are constructedand arranged such that, if desired for some reason, the user's fingerscan wrap around the bottom of the side walls to aid in holding scraper60. Side walls 67 and 68 generally are less than 4 inches high and inone non-limiting example are less than 3 inches high. In example scraper60 of FIG. 2A-2C, side walls 67 and 68, measured at the midpoint betweenmaterial removal edges 61 and 62 are approx. 2 inches high, and the topsurface of handle 64 rests approximately 2.5 inches above surface 5 whenboth edges 61 and 62 are in contact with surface 5.

In one non-limiting example shown in side view in FIG. 3A, side wall 67and 68 (the opposite side of the scraper including side wall 68 has thesame arrangement as shown in FIG. 3A for wall 67 except reversed left toright from what is shown) are not solid but have an opening therein. Inthis example, a user's fingers can wrap around the top of handle 64 andfit through open truss panel 76 in side wall 67 (and similar openings inopposite side wall 68 not shown). In one non-limiting example depictedin FIG. 3C, the opening in truss panel 76 only allows a user's thumb topartially press into the hole but not fit through it. This provides agood surface for enhancing grip of the scraper without the possibilityof having fingers get caught within the interior of the scraper.

FIGS. 3A-3C depict alternative truss panels useable with the scraper ofFIG. 2A. In scraper 35 of FIG. 3A, side wall 67 (and side wall 68)couple to ends of wall 63 over only a portion of the height of wall 63that is nearer the continuous material removal edge 61 than it is to thehandle 64. By nearer, it is meant that wall 67 (and 68) should connectwithin a distance equal to at least ½ the distance between the materialremoval edge and the leading edge 65 of handle 64 (i.e. ½ the heightextent of material removal wall 63), and preferably within ¼ thedistance between the material removal edge 61 and the leading edge 65 ofhandle 64 (i.e. ¼ the height extent of material removal wall 63). It ispreferable for side walls 67 and 68 to couple to wall 63 as close as ispractical to edge 61 to better control deformation of edge 61, withoutinterfering with the surface from which material is being removed.

Side walls 67 and 68 effectively increase the bending stiffness andreduce displacement of the ends of material removal edge 61 (near whereside walls 67 and 68 couple to ends 69 and 70 of wall 63) relative todisplacement of the midpoint of material removal edge 61 (the pointequidistant from the ends of material removal edge 61). The degree towhich bending stiffness increases due to the coupling of side walls 67and 68 to wall 63 depends on where the side walls 67 and 68 couple towall 63 (how close to the material removal edge they are coupled), theside wall thicknesses (as this relates to the wall sectional modulus)and wall material properties, and how the side walls 67 and 68 couple toother portions of scraper 60. The coupling of side walls 67 and 68 toother portions of scraper 60 is discussed below.

As can be seen in FIGS. 2A-2B, side walls 67 and 68 couple to side ends69 and 70 of wall 63 (which extends between handle 64 and continuousmaterial removal edge 61), side ends of handle 64 and side ends 79 and80 of wall 73 (where wall 73 extends between handle 64 and discontinuousmaterial removal edge 62). By coupling walls 67 and 68 to either or bothof handle 64 and wall 73, in addition to coupling to material removalwall 63, side walls 67 and 68 impart substantially larger bendingstiffness to wall 63 along the material removal edge 61 near where sidewalls 67 and 68 couple to wall 63.

In scraper 60 of FIGS. 2A-B (and scrapers 30, 35 and other scrapersdepicted in the figures), wall 63 forms an angle of approximately 45degrees with surface 5 when both material removal edges 61 and 62 are incontact with surface 5, and handle 64 of scraper 60 is oriented at anangle of approximately 0 degrees (i.e. is generally parallel) to surface5. If side walls 67 and 68 were coupled only between wall 63 and handle64, side walls 67 and 68 would be tying between two generally planarwalls that are angled with respect to each other approximately 135degrees (shown as angle 74 in FIG. 2C), and would effectively form atruss structure having a generally triangular shape (when viewed fromthe side, one truss is formed by wall 63, handle 64, and side wall 67,and a second truss is formed by wall 63, handle 64, and side wall 68),which would substantially increases the bending stiffness seen alongmaterial removal edge 61 at the locations closest to where side walls 67and 68 couple to wall 63. The angle formed between walls 67 (and 68) andhandle 64 should be less than 165 degrees to obtain sufficient benefitfrom the truss structure, preferably less than 150 degrees.

If side walls 67 and 68 coupled to both walls 63 and wall 73, they wouldform a generally trapezoidal truss structure when viewed from the side(one truss is formed by wall 63, handle 64, wall 73, and side wall 67,and a second truss is formed by wall 63, handle 64, wall 73, and sidewall 68). When side walls 67 and 68 couple between walls 63 and 73, thebending stiffness seen along the material removal edges 61 and 62 at thelocations closest to where the side walls 67 and 68 couple to walls 63and 73 is substantially increased, and is increased over the situationdescribed above where the truss shapes were triangular. When the trussties together walls 63 and 73, a substantial increase in bendingstiffness is obtained whether or not side walls 67 and 68 couple tohandle 64.

In the non-limiting example scraper 35 of FIG. 3A, handle 64 forms a topchord of a truss structure, walls 63 and 73 form angled members of thetruss, and side wall connector 85 forms the bottom chord of the truss.Bottom chord 85 extends from wall 63 to wall 73, attaching to walls 63and 73 on the side ends near the material removal edges 61 and 62. Thearea surrounded by the angled members (walls 63 and 73), the top chord(handle 64) and bottom chord 85 is the truss panel 76. In the example ofFIG. 3A, truss panel 76 is depicted as being open. If desired,additional truss members could tie various portions of walls 63 and 73,handle 64 and bottom chord 85 together. In the non-limiting examplescraper shown in FIG. 3B internal truss members 87 and 88 are added. Itshould be noted that although FIG. 3B shows two internal truss members,the arrangement and number of internal truss members is not limited.

The truss structures effectively transform bending loads applied to thetruss into tension and compression loads in the truss members. Whenlooking across the width of the material removal edges 61 and 62, thetruss structures variably transform the bending loads F_(B1) and F_(B2)applied to walls 63 and 73 along material removal edges 61 and 62 intotension and compression loads in the truss elements (the chords andangled members). That is, looking across the width of the materialremoval edges, progressively more of the applied bending load presentacross the width due to a force applied to the scraper pressing itagainst the surface is converted into tension and compression loads inthe trusses as the point of interest is moved from the midpoint of thematerial removal edges (i.e. midway between where sides walls 67 and 68couple to walls 63 and 73, the point along the width at maximum distancefrom the location where the trusses couple to wall 63) towards the endsof the material removal edges nearer the location where side walls 67and 68 couple to walls 63 and 73. This mechanism of variablytransforming input bending loads into tension and compression loads as afunction of location across the width of the material removal edgesenables the material removal edges to conform to the curvature of theunderlying surface.

The examples depicted in FIGS. 4A and 4B show alternative trussstructures that can be used with the scraper arrangement of FIG. 2A. Inone non-limiting example depicted in FIG. 4A, chord 85 connects to wall73 a distance (identified by ref. number 77 in FIG. 4A) away from thelocation of discontinuous material removal edge 62. (The opposite sideof scraper 35 will have similar construction, just flipped left to rightfrom what is shown in FIG. 4A.) The distance 77 is shown approximately ½the height of wall 73. However, a practical device could connect bottomchord 85 to virtually any location along wall 73. The ability of thetruss formed from wall 63, bottom chord 85, a portion of wall 73, andhandle 64 to transform bending loads applied to continuous materialremoval edge 61 is not substantially altered as the distance 77 isvaried. Even connecting bottom chord 85 at the joint 66 between handle64 and wall 73 (shown in FIG. 4B with a different truss panelarrangement) will be effective in altering the bending behavior of edge61, though the stiffness of wall 73 is reduced. Generally, it ispreferable not to reduce stiffness of wall 73 appreciably, as edge 62 issubject to large impact forces when chipping ice.

As mentioned previously, it is not as important for a discontinuousmaterial edge to be arranged to conform to the curvature of a surfacefrom which material is to be removed because chipping or scoringchannels in adhered material is not as sensitive to having thediscontinuous material removal edge conform to the surface shape. It isalso due to the fact that the wall 73 is typically made narrower thanwall 63 (in order to keep the surface area of teeth small to maximizepressure when teeth are pressed against harder materials such as ice).As the span of the discontinuous material removal wall narrows, a lineardiscontinuous edge is a closer approximation to the curved shape of thesurface.

Turning now to FIG. 4B, a side view of one side of non-limiting examplescraper 35 is shown. (The opposite side of scraper 35 will have similarconstruction, just flipped left to right from what is shown in FIG. 4B.)Bottom chord 85 is connected between wall 63 and the region of joint 66between handle 64 and wall 73 and truss panel 76 is solid. It shouldalso be noted that in either of the examples of FIG. 4A or FIG. 4B, thetruss panel 76 could be open or closed, or could be constructed withinternal angled members as described earlier with respect to the exampleof FIG. 3B. In FIG. 4B, since the truss panel is solid, the bottom chordand truss panel connect along essentially the entire length of wall 63(except right at the material removal edge where some clearance isprovided) and along the length of handle 64. The coupling of walls 67(and 68) with wall 63 and handle 64 forms a triangular shaped trussstructure, where wall 63 and handle 64 and bottom chord 85 provideangled members of the truss. The truss structure will act to transformbending loads applied to material removal wall 63 along material removaledge 61 into tension and compression loads as before, and will variablyconstrain bending of wall 63 over the width of wall 63. This arrangementwill substantially reduce outward displacement of material removal edge61 at locations proximate the location where side walls 67 (and 68), andmore specifically bottom chord 85 (and its equivalent in the oppositeside wall 68), couple to wall 63, compared to the outward displacementof edge 61 obtained between the locations of side wall coupling, when adownward directed force is applied by a user to handle 64 that forcesscraper 60 against the surface.

In one non-limiting example, a scraper is configured in a manner similarto scraper 60 of FIG. 2A, but both material removal edges 61 and 62 areof the continuous type. By incorporating a pair of continuous materialremoval edges, with each arranged so that the included angle formedbetween the material removal wall containing the material removal edgeand the surface at the point the material removal edge contacts thesurface is an effective angle for scraping (such as between 30 and 60degrees as described earlier for the scraper having one continuous andone discontinuous edge), provides for yet more efficient scraping forcertain types of adhered materials, one example being frost. As thescraper is moved fore and aft across a surface, each edge willalternatively be arranged for effective scraping to allow efficientmaterial removal for both fore directed motions and aft directed motions(motions away from and back towards the user). Material removal wallsare maintained at desired angles for scraping, and the dual edge designenables scraping by a user while only requiring application of a simpleforce.

The example scraper as shown in FIG. 2A incorporates a first continuousmaterial removal edge and a second discontinuous material removal edge.The scraper can be moved in a first direction to score channels in iceusing the discontinuous material removal edge. When scraper 60 is heldwith the material removal edge 62 facing away from a user and the userpushes the scraper away from their body, material removal edge 62contacts the hard material (such as ice in an automotive application) onthe surface before material removal edge 61 contacts the material.Discontinuous material removal edge 62 first breaks up the material onthe surface and continuous material removal edge 61 follows behind “inthe same motion” to clean up the surface. No flipping back and forthbetween continuous and discontinuous edges is needed. Removal of hardermaterials such as ice becomes much more efficient. In prior artscrapers, one must hold the scraper in a first orientation to scorechannels in or chip ice using a discontinuous material removal edge.Once the material has been chipped or scored, the user flips the scraperover to a second orientation and to re-scrape all the areas previouslyscraped using a continuous material removal edge.

The example scrapers disclosed herein inherently reduce or eliminatehand and wrist strain, and are much less prone to slipping and abruptorientation changes when chipping ice due to their inherently stabledesign. When a user holds a traditional scraper (which requiresapplication of a force couple to hold the scraper at an effectivescraping angle), when the scraper is jammed into ice substantial strainmay occur in the user's hand and wrist (from abrupt stopping and torquegeneration when impacting thick, hard material such as ice). The scrapermay also suddenly change its orientation as it either breaks through iceor slips over the ice surface, which can result in scraped knuckles forthe user.

Analysis of a computer finite element model of scraper 60 of FIG. 2A(but using the side panel construction depicted in FIG. 2F) wasperformed. The material properties, dimensions and geometry of themodeled scraper were chosen to enable continuous material removal edge61 to conform to a curved surface with a radius of curvature ofapproximately 1.5 meters (1.5 meters is the smallest expected radius ofcurvature of vehicle glass), with an input force applied by a user inthe range between 5 and 10 lbs. of force. The model assumed use of ABSmaterial with 3 mm wall thickness, the width of the continuous materialremoval edge 61 was chosen to be 110 mm, material walls 63 and 73 wereeach angled at 45 degrees relative to a flat surface, the overall heightof scraper 60 above the surface was chosen to be 50 mm, and the spacingbetween material removal edge 61 and 62 was chosen to be 120 mm. Forease of modeling, the handle 64 was fixed and an input force of 10 lbs.was applied. The force was directed upward, normal to the surface anddistributed across material removal edge 61. Application of the forceresulted in deflection of the center of material removal edge 61 ofapprox. 1.5 mm relative to deflection of the ends of the materialremoval edge 61. In other words, the differential deflection obtainedfor the material removal edge, which is the difference between themaximum and minimum deflection of the edge over its length, was 1.5 mm.The height of an arc with a radius of 1.5 meters over a span of 110 mmis approx. 1 mm. Therefore, with 10 lbs. of force applied the examplescraper model shows it will deflect sufficiently for it to conform tothe 1.5 meter radius of curvature.

In the above example, the distance between material removal edges 61 and62 was chosen to be 120 mm. Examples are not limited to this spacing.Spacing larger than or smaller than 120 mm are contemplated herein. Inone non-limiting example, the spacing is equal to or greater than 70 mm.In one non-limiting example, the spacing is equal to or greater than 100mm. In one non-limiting example, the spacing is equal to or greater than120 mm. In one non-limiting example, the spacing is equal to or greaterthan 150 mm. In one example, the spacing is equal to or greater than 200mm. In one non-limiting example, the spacing is equal to or greater than300 mm. For spacing larger than approx. 150 mm, it may be desirable toadd stiffening ribs to sections of the scraper that are not intended todeform, such as handle 64. Stiffening ribs can also be added to portionsof walls 63 and 73, but should not extend too close to the materialremoval edges or they could cause the bending stiffness of portions ofthe material removal edges to increase in undesirable ways.

In one non-limiting example depicted in FIG. 2D, single structure 27transforms bending loads applied to continuous material removal edge 21(and discontinuous material removal edge 22) into tension andcompression loads in the structure 27. Though scraper 20 is depicted ashaving a continuous and a discontinuous edge, use of a pair ofcontinuous material removal edges is also contemplated. Additionally,either or both of the edges may be pre-biased into curved shapes withthe same or different radii of curvature, with either concave or convexshapes in unloaded conditions. Scraper 20 is configured to deform toconform to surfaces with a concave shape. The ends of material removaledges 21 and 22 deform substantially more than the midpoints. Scraper 20is depicted flipped upside down from the orientation of scraper 60 inFIG. 2A.

Structure 27 is coupled to the midpoint of material removal wall 23 ofscraper 20. Structure 27 couples to wall 23 over essentially its entireheight, though coupling over the entire height is not required.Structure 27 also couples to the midpoint of material removal wall 33over essentially its entire height, though coupling over the entireheight is not required. Structure 27 is shown coupled to materialremoval wall 23 near the continuous material removal edge 21 and to wall33 near material removal wall 33. In one non-limiting example, structure27 couples to walls 23 and 33 as close as practical to edges 21 and 22so as not to touch curved surface 5. Structure 27 also couples to handle24. However, coupling to handle 24 is not required.

Structure 27 can effectively transform bending loads applied to edges 21and 22 into tension and compression loads if it is only coupled to walls23 and 33. Alternatively, structure 27 can transform bending loadsapplied to edge 21 into tension and compression loads if it is onlycoupled to wall 23 and handle 24. Structure 27 need not couple to wall33 near the location of discontinuous material removal edge 22 if it isonly necessary to transform bending loads applied to material removaledge 21 into tension and compression loads (that is, only edge 21 isdesired to conform to the underlying surface curvature). In this case,structure 27 could be coupled to any portion of wall 33. If it isdesired for discontinuous material edge 22 to also conform to a concavesurface, then structure 27 should couple to wall 33 near the location ofmaterial removal edge 22, as shown, but sufficiently far away from theedge so as not to contact surface 5.

In one non-limiting example depicted in FIG. 2E, scraper 29 incorporatesa pair of continuous linear material removal edges 21 and 26. Edge 21 isarranged so as to conform to a surface with concave curvature, and edge26 is arranged to conform to a surface with convex curvature. Althoughmaterial removal edges 21 and 26 are both depicted as being continuousand linear, either of material removal edges 21 and 26 could beconfigured as discontinuous material removal edges, and either edgecould be configured to conform to concave or convex surfaces byreversing the connection of structure 27. Additionally, either or bothof the edges may be pre-biased into curved shapes with the same ordifferent radii of curvature, into either concave or convex shapes inunloaded conditions. Structure 27 couples to wall 23 near the locationof material removal edge 21, near the midpoint of edge 21, and alsocouples to wall 33 near material removal edge 26, near the ends of edge26. Structure 27 may but need not couple directly to handle 24, and maybut need not connect to walls 23 and 33 over their entire extent. It issufficient for structure 27 to only couple to walls 23 and 33 overportions of walls 23 and 33 near the material removal edges 21 and 26.Preferably, structure 27 couples as close as practical to materialremoval edges, without interference by the surface, for whichever ofwalls 23 and 33 are desired to conform to the curvature of theunderlying surface.

In one non-limiting example depicted in FIG. 2F, scraper 30 incorporatesa continuous material removal edge 75 which is pre-biased to have acurved shape in its unloaded condition. Edge 75 in this case is formedfrom a strip or brass that is insert molded into the housing of scraper30. Scraper 30 is similar to scraper 60 of FIG. 2A, except that thetruss panel 76 has an opening therethrough, and the continuous materialremoval edge 75 is pre-biased into a curved shape. Pre-biasing can beuseful to alter the pressure applied to a surface along the contact lineof the continuous material removal edge with the surface, and toaccommodate a wider variety of surface curvatures. In any of the examplescrapers described herein, a continuous material removal edge havingsome degree of curvature in an un-loaded state could be used. Bypre-biasing a continuous material removal edge to have a curved shape inits un-loaded condition, it is possible to construct a material removaledge that can conform to convex, flat and concave surfaces.

Example scraper 30 of FIG. 2F incorporates bending load transformingstructures 67 and 68 (68 is on opposite side of scraper 60 from side 67,and is not visible in FIG. 2F) attached to ends of material removal wall63 incorporating material removal edge 61. Edge 61 and at least aportion of wall 63 proximate edge 61 of scraper 30 is pre-biased to haveconcave curvature in an unloaded state. Such a pre-biased edge/wallcould conform to any concave shaped surface with a radius of curvaturegreater than the radius of curvature of the un-deformed edge 75, as wellas a range of convex curved surfaces, when scraper 30 is pressed againstsuch curved surfaces. The material removal edge 75 in this case isbiased such that the midpoint of the edge (which is the location alongthe edge that can be maximally deformed with applied bending loads)contacts a surface from which material is to be removed first, forsurfaces of interest.

In one non-limiting example, a scraper has a removable blade assemblywhere the removable blade assembly incorporates either a pair ofcontinuous material removal edges or a first continuous material removaledge and a second discontinuous material removal edge. Example removableblade assemblies are shown in FIGS. 5A-5E. Removable blades are usefulfor scrapers as they allow a blade to be replaced if it is damagedwithout having to replace the entire scraper. Injection molded removableblades can be manufactured at low cost.

In one non-limiting example, a continuous material removal edge (oredges) of a removable blade are constrained to provide variabledisplacement of the continuous material removal edge or edges over theirrespective widths (although a discontinuous material removal edge ifincorporated in the removable blade may also be so constrained ifdesired). The removable blade incorporates structures that variablytransform bending loads applied across the material removal edge(s) intotension and compression loads in the structures, to vary the bendingstiffness of the material removal edges over their respective widths.Structures can be incorporated in removable blades so that materialremoval edges can deform to conform to either convex or concavesurfaces, or both. Example scrapers incorporating removable blades arediscussed in more detail in subsequent sections.

Removable blade assemblies can be configured similarly to theconfigurations of scrapers described earlier, with the one exceptionthat handle 64 of FIG. 2A is replaced with top surface 54 that couplesthe material removal walls together. In most applications, top surface54 will be smaller than handle 64 as the scraper will have a separatehandle. A force applied by a user to the scraper handle can bedistributed across the entire width of the blade top surface 54. Thisaids in more evenly distributing the input force across the entire widthof the material removal edges. In some examples, a replaceable bladeassembly can be made similar to earlier described scrapers (such asscrapers 20, 29, 30, 35, and 60) but including features that allow theblade assembly to removably connect with a separate scraper handle. Topsurface 54 may include coupling features useful for securing theremovable blade to a separate handle structure of some type.

Removable blade assemblies incorporate a pair of material removal wallswhich each incorporate a material removal edge. The pair of materialremoval edges are spaced apart from each other. The material removaledges can be any of the material removal edge types described earlier(continuous or discontinuous, linear or pre-biased into a curve), whereat least continuous material removal edges are constructed and arrangedto conform to the curvature of an underlying surface (which can beconvex, concave, or flat).

There are numerous ways in which a removable blade assembly can beattached to a scraper body or handle. In some examples, the removableblade assembly snaps into a handle, in other examples it slides intoplace in the handle, or it may use clips, threaded fasteners, or otherknown fastening methods. Holes 59 are shown in FIGS. 5A and 5B which canbe used to couple with snap features of a separate scraper handleproviding one coupling method, but examples disclosed herein are notlimited in the coupling features used to secure removable bladeassemblies to scraper handles.

The scraper handle and removable blade assembly are arranged such that aforce applied to the handle to force the removable blade against asurface is transferred to the top region 54 of the removable bladeassembly located between the pair material removal edges, so that bothmaterial removal edges can simultaneously be loaded against the surface.Structures, such as ridges, walls, or other mechanical stops can beincorporated into either the removable blade assembly, scraper body, orboth to absorb fore-aft loads and torque loads that may be generatedwhen the scraper impacts harder materials when scraping the surface, sothat snap or coupling features that affix the blade assembly to thehandle do not need to withstand the impact loads. In one non-limitingexample, structures separate from attachment features that couple theblade assembly to the scraper handle protrude from the scraper handleand fit through one or more holes 59 or slots in the top surface of aremovable blade, to absorb fore-aft loads and torques. The holes canalso be used as alignment features for assembly of the blade to thescraper body, and may also be used to alter the bending stiffness of thematerial removal walls of the removable blade. In one non-limitingexample, the removable blade assembly slides in place between walls inthe scraper body that absorb fore aft loads and torques.

Removable blade assembly 50 incorporates a pair of continuous materialremoval edges 51 and 52, as shown in FIGS. 5A and 5B. The view shown inFIG. 5B is flipped over from the view shown in FIG. 5A, to show theinterior surfaces of removable blade 50. Side walls 57 and 58 connectends of material removal walls 53 and 43 to each other at least atlocations near the material removal edges. Preferably, side walls 57 and58 couple to material removal walls 43 and 53 as close as is practicalto material removal edges 51 and 52 without interfering with the surfacefrom which material is to be removed, for whichever of the edges areconstructed and arranged to conform to the curvature of the surface whenpressed against it.

Side walls 57 and 58 are depicted as solid and are attached to walls 53and 43 along the entire height of material removal walls 53 and 43(except some clearance is provided near the material removal edges), atopposite ends of blade assembly 50. When viewed from the sidestrapezoidal shaped truss structures are formed, where side walls 57 and58 form the bottom chords and panels of the truss structures, blade topsurface 54 forms the top chord (which is analogous to the role handle 64performs in the example scrapers of FIGS. 2A-2C, 3A-4B), and materialremoval walls 53 and 43 form angled members of the truss structures.Though side walls 57 and 58 (58 not visible in FIG. 5A) are depicted ashaving solid panels, any of the previously described truss panels can beused with the replaceable blade assemblies, such the truss panels shownin FIGS. 3A-3C.

The truss structures variably transform bending loads applied to thematerial removal edges 51 and 52 into tension and compression loads inthe truss structures, where the degree to which bending loads aretransformed into tension and compression loads varies as a function oflocation along the material removal edges, with relatively more bendingload transformed into compression and tension loads as the location ofinterest along the material removal edges gets closer to the pointswhere the side walls 57 and 58 couple to the material removal walls 53and 43.

The material removal edges of removable blade assembly 50 will conformto a surface with convex curvature when a force is applied that loadsblade assembly 50 against the surface, with both edges 51 and 52 againstthe surface. The edges of blade assembly 50 will deform in the samemanner as described for the earlier scraper examples. Similarly, aremovable blade assembly could be formed with a single truss structure58 as in blade assembly 45 of FIG. 5D coupling walls 53 and 43 togetherat the midpoints of walls 53 and 43. A blade configuration with thesingle truss structure coupling to midpoints of walls 53 and 43 isconstructed and arranged to conform to a surface with concave curvature,when a force loads the blade assembly against a concave surface and thematerial removal edges are in contact with the surface. A thirdremovable blade assembly example 55 is shown in FIG. 5E and is analogousto the example depicted in FIG. 2E where structure 53 couples themidpoint of material removal wall 43 to the ends of a material removalwall 43. It is also contemplated that the truss structures of FIGS. 5Dand 5E can be used with blade assemblies that incorporate a pair ofcontinuous material removal edges, with any of the previously describedvariations in width, curvature, etc.

Any of the above truss arrangements for a removable blade assembly canbe used with material removal walls pre-biased into a curve (i.e.pre-shaped such that they are not straight when in an unloadedcondition) if desired, to accommodate a wider range of surfacecurvatures including surfaces with either convex or concave curvature.The pair of material removal edges may be curved the same ordifferently. The pair of material removal edges may have different radiiof curvature. The pair of material removal edges may be pre-biased intoconvex or concave shapes in an unloaded condition.

It should also be noted that the pre-biasing of a material removal edgecan aid in removing material from flat surfaces, as the pre-biasrequires a certain amount of force to be applied to overcome the bias.This alters the force distribution across the material removal edges andwill distribute relatively more force to the initial contact area in themiddle of the blade (for example blade 50 and also edge 75 of examplescraper 30 in FIG. 2F) with respect to force applied at the ends ofblade 50 (or scraper 30), when the blade is pressed against either aflat or convex shaped surface.

Although material removal edges 51 and 52 are depicted in FIGS. 5A and5B as having the same width, this is not required. It may be desirableto have one continuous material removal edge be narrower than the other,in order to facilitate scraping smaller surfaces such as vehicle sideview mirrors. Also, though a removable blade assembly is being discussedhere, a scraper similar to the scraper of FIG. 2A incorporating a pairof continuous material removal edges, where one continuous materialremoval edge is narrower than the other is also contemplated herein.

FIG. 5C depicts a non-limiting example removable blade assembly 40 whichincorporates one continuous material removal edge 41 in material removalwall 43 and one discontinuous material removal edge 42 in materialremoval wall 33. Side walls 47 and 48 couple between walls 43 and 33,and also to top surface 44. The pair of material removal edges may bestraight when the removable blade is in an unloaded condition.

Alternatively, one or both of the material removal edges may bepre-biased to have either a concave or convex curvature when in anunloaded condition. They may have the same curvature or differentcurvature. They may have the same or different widths. In one example,discontinuous material removal edge 42 has a narrower width thancontinuous material removal edge 41. In one example, a continuousmaterial removal edge is pre-biased into a curved shape (in an unloadedcondition) and a discontinuous material removal edge is not pre-biasedinto a curved shaped. Removable blade 40 incorporates truss structuresas before. Any of the truss structures previously described with respectto a full scraper can be applied to the removable blade assembly.

In one non-limiting example, a removable blade assembly may be affixedwith a fixed orientation to the scraper handle, such that it can only befit to the scraper handle in a single orientation. In one non-limitingexample, a removable blade assembly may be affixed to the scraper handlesuch that either material removal edge can be oriented to face outward,such that either material removal edge can act as a leading edge whenthe scraper is pushed forward along a surface by a user. In onenon-limiting example, a scraper handle which accepts a removable bladeassembly may incorporate a pivoting structure as depicted in FIG. 8 thatallows either edge of the removable blade to function as a leading edgeof the scraper when in use. Handle 83 includes pivot structures 89 thatfit around pivot structures 86 of blade assembly 84. Pivot pin 82 fitsinto holes in pivot structures 89 and 86, and is used to transfer forceform handle 83 to blade assembly 89. Pivot pin can be made removable sothat blade assembly 89 can be changed is desired. However, in otherexamples, pivot pin is permanently affixed so that blade assembly 89 isno longer replaceable. The range of rotation of handle 83 with respectto blade assembly 89 should be greater than 90 degrees, and preferablyis greater than 135 degrees, and more preferably is 180 degrees.

In one non-limiting example, a scraper body which accepts a removableblade may incorporate a rotating structure that allows the removableblade to be rotated such that either material removal edge of the bladecan be oriented as a leading edge. A rotationally coupled blade assemblyshould have lockable detent positions, so the assembly cannot rotatewhen being used to scrape. It should be noted that a scraperincorporating a pivoting structure or a rotating structure or acompliant structure between an elongated handle and the blade assemblyneed not have a user removable blade. The blade assembly may bepermanently affixed to the elongated handle during manufacture.

In one non-limiting example depicted in FIG. 6, elongated handle 94 isaffixed to scraper blade assembly 95 having a pair of material removaledges (as in the various example scrapers and blade assemblies disclosedherein) such that the center of mass of the complete assembly no longerresides within the envelope of the pair of material removal edges. Anelongated handle which extends along the length of the scraper asignificant distance beyond the location of one of the material removaledges could be affixed to handle surface 64 as shown in FIG. 6, or becoupled to other structures as shown in FIGS. 8 and 9. In theseexamples, gripping the handle at a location outside of the projectedenvelope of the material removal edges requires the user to apply aforce couple to hold the scraper in place against the surface, butprovides the benefit of extending the length of the scraper forincreased reach. Again, the blade assembly 95 can be removable by a useror may be fixed to the elongated handle during manufacture.

Example scraper 90 depicted in FIG. 6 shows a blade 95 compliantlycoupled to a first end of a scraper body 94. The blade assembly 95 maybe removable or may be fixed to scraper body 94 during manufacture. Theblade assembly 95 incorporates a pair of continuous material removaledges 91 and 92, though any of the arrangements disclosed earlier formaterial removal edges is contemplated for use here (edges may becontinuous or discontinuous, straight or pre-biased into a curved shapewith same or different curvatures, and may be the same or differentwidths, in any combination). The scraper elongated handle 94 may includea third material removal edge 93 which may be of the discontinuous,toothed type or may be continuous, coupled to a second end of thescraper handle 94. The scraper handle may be of any desired length. Inthe example of FIG. 6, the length is sufficient to allow a single handof a user to grasp the scraper handle 94. In one non-limiting example,the scraper handle is elliptically shaped. In other examples, a muchlonger scraper handle may be used to allow a user to grasp the scraperhandle 94 with both hands, and to reach farther distances away from theuser.

In the example scraper of FIG. 6, the scraper is constructed andarranged so that all three material removal edges can simultaneouslycontact the surface from which material is to be removed. This ispossible because some relative angular rotation of the blade assembly 95with respect to handle 94 is allowed (through the compliant mounting ofthe blade assembly to the handle). Relative angular rotation could alsobe obtained if the blade assembly were pivotably coupled to the scraperhandle (using a pivot as in or similar to the pivot shown in FIGS. 8 and9). When scraper 90 is arranged so that all three material removal edgesare in contact with surface 5, the scraper handle arches up away fromthe surface a sufficient distance so that a user can wrap their glovedhand around the scraper handle 94 with sufficient clearance to fit theusers gloved fingers between the underside of the scraper handle 94 andthe surface 5. The clearance should be at least 1 inch, preferably atleast 1.5 inches, and more preferably more than two inches between thebottom of the handle and the surface. The blade assembly 95 iscompliantly mounted to the scraper handle 94 via a compliant gasket 96(which may be formed from a sheet of elastomeric material, or may beovermolded to the scraper body 94 or the removable blade 95) so that theremovable blade can rock slightly.

In another example, a scraper with an elongated scraper handle, whichmay be a tubular shaped handle with an arbitrary cross sectional shape,is constructed and arranged with a first blade assembly having a pair ofmaterial removal edges coupled to one end of the handle, and a secondblade assembly coupled to the opposite end of the handle. The scrapercan be used such that either the pair of material removal edges coupledto the first end of the scraper handle simultaneously contact thesurface while a material removal edge or edges of the second bladeassembly is/are held so as not to contact the surface, or a materialremoval edge or edges of the second blade assembly contact the surfacewhile the scraper is held such that the material removal edges of thefirst blade assembly do not contact the surface. A long scraper handlemay incorporate a telescoping handle arrangement that allows the lengthto be extended. Any of the blade assemblies disclosed herein can be usedas the first and second blade assemblies.

Turning to FIGS. 9A and 9B, non-limiting example scraper 99 is depicted.FIG. 9B shows an exploded view of scrapper 99 turned upside down formthe view depicted in FIG. 9A. Scraper 99 pivotably couples bladeassembly 60 a, which in this example is similar to scraper 60 of FIG. 2Awith the addition of pivoting features, to elongated handle 94 a. Bladeassembly 60 a includes handle 64 a which the user can grasp if desired.Handle 64 a is positioned between the pair of material removal edges 61a and 62 a, so that the user has an option to grasp the scraper in alocation that does not require application of a force couple. Scraper 99incorporates a pivot for coupling the blade assembly 60 a to theelongated scraper handle 94 a. The specific arrangement of the pivot isnot limited, and any known pivot assembly can be used. In this example,a separate pivot pin 97 is fit through holes 89 a in the end of handle94, and through holes 131 and 132 in internal ribs 98 of blade assembly60 a. Holes 104 and 105 in blade assembly 60 a are larger in dia. thanthe diameter of pivot pin 97 and holes 131 and 132 in ribs 98, so thatforce from the handle 94 a is primarily transferred to the bladeassembly from the elongated handle to the pivot pin and through internalribs 98. This helps distribute more input force to assembly 60 a nearthe middle of edges 61 a and 62 a, which is beneficial when using thescraper against flat surfaces. In other examples, ribs 98 may not bepresent and the pivot couples forces from the handle into side walls 67and 68 (wall 68 not shown in this view). Pivotably attaching a bladeassembly to an elongated handle has the benefit of allowing the user'shand/arm orientation with respect to the surface to be varied morewidely for improved ergonomics while still helping ensure both materialremoval edges stay in simultaneous contact with the surface, and allowsthe device to be stowed away more easily.

The pivot allows the handle 94 a to be rotated such that either materialremoval edge 61 a or 62 a can become a leading edge. The center of thepivot resides below handle 64 a. This allows a user to place their handon handle 64 a to use blade assembly 60 a similarly to how earlierdescribed hand held scrapers (such as scraper 60 in FIG. 2A-2C) areused. It is desirable to locate the pivot center as low as possible inblade assembly 60 a, close to the surface. This reduces the overturningmoment of the scraper and helps keep the blade assembly 60 a frompivoting when it impacts hard material. However, it should be noted thatit is not required that a pivot allow the user to place their hand ontop of the blade assembly. Useful examples may use a pivot that extendsabove the top surface of surface 64 a, as shown in FIG. 8. If a bladeassembly similar to the scraper shown in FIG. 2D is used, ribs would belocated on the sides so that force from the handle can be applied to theends of the blade assembly (away from the single truss structure).

Various scrapers incorporating an elongated handle are contemplatedherein. Any of the hand-held scrapers and blade assemblies (as disclosedin FIGS. 2A-5E) may be used on one or both ends of an elongated scraperhandle, in any combination. Any of the previously described trussstructures and pre-bias curvatures of material removal edges can beused. Any of the disclosed scrapers or blade assemblies may be used onone end of an elongated handle, and individual material removal edgescan be used on the opposite end of the elongated handle. Any of thehand-held scrapers or blade assemblies can be permanently or removablyattached to the elongated handle. Any of the hand-held scrapers or bladeassemblies can be fixed, compliantly coupled, pivotably or rotationallycoupled to the elongated scraper handle. The elongated scraper body mayhave any desired length, accommodating either a single hand or both of auser's hands. The elongated scraper body may have extendable length. Theelongated handle may incorporate a brush or pad for removal of snow.

In any of the previously described examples incorporating adiscontinuous material removal structure, the discontinuous materialremoval structure can be formed from brass material. Non-limitingexample discontinuous material removal structure 100 is shown in FIG. 7.Structure 100 is formed by cutting an extrusion to length 101. Fins 102protrude from the structure and are used to score channels in hardmaterial like ice adhered to a surface. Upper structures 103 are used tohelp hold the extrusion in place. Typically, a separate discontinuousmaterial removal structure will be insert molded so that the upperportions of structure 100 are encapsulated in plastic of the scraperbody. The upper structures shown are representative. Any extrudableshape can be used for these structures. Consideration should be made forthe insert molding process to allow plastic to flow around thestructures and maintain wall thickness specifications and flowproperties. Other features could be machined if desired. Other methodsof manufacturing a brass discontinuous material removal structure suchas metal injection molding, casting, machining or other known metalforming processes are also possible, and example scrapers disclosedherein are not limited in the method used to form a brass discontinuousmaterial removal structure.

Use of brass (which has higher Young's modulus than prior art polymermaterials) allows thinner wall sections to be used which improveschipping/scoring performance. Chipping of ice in particular depends onthe pressure exerted on the ice. The pressure at the interface of thediscontinuous material removal edge with hard materials such as ice canbe increased (while keeping the input force constant) by reducing thecontact area. Using higher modulus brass allows thinner wall teeth to beused, which results in higher pressures at the interface of each toothwith the ice (assuming the number of teeth remain constant). Designs canuse more teeth if desired with the same or reduced spacing for improvedchipping. Discontinuous material removal edges formed of brass exhibitan improved ability to chip ice or score other harder materials comparedto discontinuous material removal edges formed of polymer materials.

scrapers have two spaced apart material removal edges arranged forsimultaneous contact with a surface. Example hand held scrapers have ahandle located between the two spaced apart edges. When both materialremoval edges are in contact with the surface, the handle is raisedsufficiently above the surface so that the surface does not appreciablyinterfere with the user's hand. The material removal edges are held atangles with respect to the surface that are effective for removingmaterial (such as between 30 and 60 degrees). By constructing scraperscapable of having two edges in simultaneous contact with the surfacewith a handle spaced between the edges, the scrapers are stable againstthe surface and only a simple force is needed to hold them in placeregardless of the orientation of the surface, while maintaining theedges at angles effective for scraping, preferably in the range of 30-60degrees. Hand held scrapers, such as those shown in FIGS. 2A-4B havetheir center of mass located somewhere between the two edges in topview, when the scraper is placed on a flat horizontal plane, to ensurethe scrapers sit stably and will not easily overturn or rotate in use.

Example scrapers have at least one continuous material removal edge thatis constructed and arranged to conform to the shape of a surface whenpressed against the surface and a second edge which may be continuous ordiscontinuous. A second continuous edge if used can be constructed andarranged to conform to the curvature of the surface, but it is notrequired. Continuous material removal edges may be pre-biased such thatin their unloaded state, the edges have a curvature. Edges may bepre-biased into convex or concave shapes. In example scrapers having twocontinuous material removal edges, the unloaded curvatures of the edgescan differ. One edge may be linear while the second edge is pre-biasedinto a curved shape. Both edges may be pre-biased into curved shapes,where the radius of curvature may be the same or different. One edge maybe pre-biased in its unloaded state into a concave shape, while theother material removal edge is pre-biased into a convex shape in itsunloaded state, with the same or different radii of curvature. The edgesmay be the same width or different widths.

Example scrapers may have one continuous material removal edgeconstructed and arranged to conform to the curvature of a surface and asecond material removal edge that is discontinuous. The discontinuousedge may be constructed and arranged to conform to the curvature of thesurface, but this is not required. Example scrapers with one continuousand one discontinuous material removal edge are constructed and arrangedto hold the edges at angles with respect to the surface effective forscraping, preferably in the range of 30-60 degrees. The edges may be thesame width or different widths.

Example scrapers may have material removal edges that are integral tothe scraper body or separate components may be used. Plastic edges canbe formed directly in an injection molded scraper. Separate componentscan be used for either or both of the continuous and discontinuousmaterial removal edges. A strip of brass material can be insert moldedin one end of a material removal wall to provide a brass continuousmaterial removal edge. A brass component having teeth or ridges (formedas an extrusion, a casting, by machining or metal injection molding, orother known metal forming techniques) can be insert molded in the end ofthe material removal wall arranged to incorporate a discontinuousmaterial removal edge.

Side walls of example scrapers couple together a pair of materialremoval walls containing a first and a second material removal edges,where the material removal edges can be either continuous ordiscontinuous. The side walls may be formed as truss structures wherebending loads applied to the material removal edge or edges aretransformed into tension and compression loads in the top and bottomchords of the truss.

In other example scrapers, truss structures couple to the middle of amaterial removal wall, near the location of a material removal edge, toallow the edge to deform to conform to surfaces with concave curvature.Example scrapers may have edges constructed and arranged to conform toconvex or concave surfaces in any combination. Any of these edges can bepre-biased into convex or concave shapes, in any combination. The edgesmay be the same width or different widths, the edges may be pre-biasedin different amounts. All possible combinations of edges (continuous anddiscontinuous), deformation (convex or concave shape with same orvarying radii of curvature), with any width are contemplated herein.Truss structures may have truss panels which can be either open orclosed. Open truss panels may have additional angled members.

An elongated handle can be affixed to the example scrapers and bladeassemblies described herein in order to extend the reach of anindividual. The blade assembly can be rigidly affixed, can be pivotablyattached, or be compliantly attached to the elongated handle. The bladeassemblies can be user removable or fixed to the handle duringmanufacture. Removable blade assemblies can be formed from plastic,brass, or a combination thereof. Removable blades can be replaced by auser if they become dented, damaged or broken, without having to replacethe entire scraper. The blade assembly can have handle that couples topends of material removal walls together on which a user can apply asimple force. Using a pivot also allows the elongated handle to fullyrotate around the blade assembly so that either material removal edgecan be used as a leading edge. The elongated handles can be of anylength, and may be extendable by the user.

Any of the described blade assemblies could also be coupled to the farend of an elongated handle. Alternatively, single edge assemblies(continuous or discontinuous) can be attached to the far end of theelongated handle. In one non-limiting example, a blade assembly having adiscontinuous material removal edge and a continuous material removaledge couples to one end of an elongated handle, and an assembly with asingle continuous material removal edge is attached to the other end ofthe elongated handle.

If a long handle is attached to blade assembly structures describedherein, the handle 64 and grip area present in the hand-held scraperversions can be substantially reduced in size if desired, and willresemble the removable blades depicted in FIGS. 5A to 5E. If the usercan grip the long handle, there is no need to provide a grip locationbetween the pair of material removal edges.

In some examples, a blade assembly is rotationally coupled to anelongated handle. This allows either of the pair of material removaledges to be made leading. A rotationally coupled blade assembly shouldhave lockable detent positions, so the assembly cannot rotate when beingused to scrape. A scraper can be both rotationally and compliantlymounted to a long handle, improving the ability to keep both edges incontact.

Use of a long handle provides design flexibility as material removalstructures can be added to the far end of the long handle. In onenon-limiting example, a scraper has an elongated handle which at one endattaches to a blade assembly comprising a pair of continuous materialremoval edges with at least one edge configured to conform to thecurvature of a surface from which material is to be removed, asdescribed earlier. Attached to the other end of the elongated handle isa single discontinuous material removal edge.

A number of implementations have been described. Nevertheless, it willbe understood that additional modifications may be made withoutdeparting from the scope of the inventive concepts described herein,and, accordingly, other embodiments are within the scope of thefollowing claims.

What is claimed is:
 1. A scraper for removing adhered material from asurface having a curved shape, comprising: a first material removal wallcomprising a first material removal edge which is continuous, the firstmaterial removal edge capable of being deformed to conform to the shapeof the surface, a second material removal wall comprising a secondmaterial removal edge which is discontinuous, the first and secondmaterial removal edges spaced apart from each other, a handle forgripping the scraper, a projected location of the handle located betweenprojected locations of the first and second material removal edges, afirst structure coupled to the first material removal wall near thefirst material removal edge and to one or both of the handle and thesecond material removal wall forming a first truss, to variablytransform bending loads applied to the first material removal edge intotension and compression loads in the first truss, wherein the handle ismechanically coupled to top ends of the first and second materialremoval walls opposite the ends of the first and second material removalwalls incorporating the first and second material removal edges, whereinthe scraper is constructed and arranged such that the continuous anddiscontinuous material removal edges can make simultaneous contact withthe surface; wherein included angles, formed between the first andsecond material removal walls and the surface, when both the continuousmaterial removal edge and the discontinuous material removal edge of thescraper are in contact with the surface, are effective for scraping. 2.The scraper of claim 1 wherein the first material removal edge ispre-biased to have curved shape in an unloaded condition.
 3. The scraperof claim 1 wherein the first structure couples to the midpoint of thefirst material removal wall and also couples to the second materialremoval wall.
 4. The scraper of claim 1 further comprising a secondstructure, wherein the second structure is coupled to the first materialremoval wall near the first material removal edge, and to one or both ofthe handle and the second material removal wall forming a second truss,wherein both the first and second trusses comprise truss first andsecond panels; wherein the first and second trusses variably transformbending loads applied to the first material removal edge into tensionand compression loads in the second truss, wherein the first and secondtrusses form first and second side walls of the scraper.
 5. The scraperof claim 4 wherein the first and second truss panels are open.
 6. Thescraper of claim 5 wherein the openings in the first and second trusspanels are not large enough to allow a user's thumb to fully penetratethrough the opening.
 7. The scraper of claim 1 wherein the firstmaterial removal edge is made of brass.
 8. The scraper of claim 1wherein the second material removal edge is made of brass.
 9. Thescraper of claim 1 wherein the scraper is constructed and arranged suchthat it can fit into typical sized glove boxes and storage bins ofautomotive vehicles.
 10. The scraper of claim 1 wherein when the scraperis pressed against a surface having a radius of curvature greater thanor equal to 1.5 meters with a force applied to the handle of 50N, theforce applied by the first material removal edge to the surface is atleast 10 N at every point along the width of the first material removaledge.
 11. The scraper of claim 10 wherein the width of the firstmaterial removal edge is at least 100 mm.
 12. The scraper of claim 1wherein the handle is mechanically coupled to top ends of the first andsecond material removal walls over the entire widths of the top ends ofthe first and second material removal walls.
 13. The scraper of claim 1wherein the handle is arranged such that the palm of a user's hand canrest on the handle and the user's fingers can rest on either of thefirst or second material removal walls, to allow the user to apply aforce to the handle with their palm and to apply a force to either ofthe first or second material removal walls with their fingers.
 14. Thescraper of claim 1 wherein the projected location of the center of massof the scraper is located between the projected locations of the firstmaterial removal edge and the second material removal edge.
 15. Thescraper of claim 1 wherein when the first and second material removaledges are in contact with the surface, the handle is sufficiently abovethe surface so that the user's thumb and little fingers can rest on theside walls of the scraper without interference from the surface.
 16. Thescraper of claim 1 wherein the included angles are between 30 and 60degrees.
 17. The scraper of claim 1 wherein the first and secondmaterial removal edges are spaced apart a distance greater than 70 mm.18. The scraper of claim 1 wherein the first truss has a shape, wherethe shape is one of the group of shapes consisting of: triangular andtrapezoidal.
 19. The scraper of claim 1 wherein the width of the secondmaterial removal edge is narrower than the width of the first materialremoval edge.
 20. A scraper for removing adhered material from asurface, comprising: a first material removal wall comprising a firstcontinuous material removal edge and a second material removal wallcomprising a second continuous material removal edge, wherein the firstand second material removal edges are spaced apart from each other,wherein the first and second material removal edges are capable of beingdeformed to conform to the shape of the surface, a handle for grippingthe scraper located between projected locations of the first materialremoval edge and the second material removal edge, wherein the handle ismechanically coupled to top ends of the first and second materialremoval walls, opposite ends of the first and second material removalwalls that incorporate the first and second material removal edges,wherein the scraper further comprises a first structure coupled to thefirst material removal wall near the first material removal edge andcoupled to the second material removal wall near the second materialremoval edge forming a first truss, to variably transform bending loadsapplied to the first material removal edge and the second materialremoval edge into tension and compression loads in the first truss,wherein the scraper is constructed and arranged such that the first andsecond material removal edges can make simultaneous contact with thesurface, and; wherein included angles, formed between the first andsecond material removal walls and the surface when both the firstmaterial removal edge and the second material removal edge of thescraper are in contact with the surface, are effective for scraping. 21.The scraper of claim 20 wherein the first material removal edge ispre-biased to have curved shape in an unloaded condition.
 22. Thescraper of claim 21 wherein the second material removal edge ispre-biased to have curved shape in an unloaded condition.
 23. Thescraper of claim 22 wherein the pre-biased curvature of the firstmaterial removal edge is different from the pre-biased curvature of thesecond material removal edge.